There are known, prior art designs and methods of manufacture for RFID tags. For example, U.S. Pat. No. 9,064,199 (Nitta) describes a flexible RFID tag design with a continuous body that includes an RFID antenna that is close to the flexible material. The RFID antenna tag base itself is made of a flexible material. The antenna is configured as a conductive thread.
The tag base is attachable to a flexible material product and has an RFID inlay or module provided for the tag base, having an IC chip and an RFID antenna, and capable of performing wireless data communication. The tag base is comprised of a flexible material, and the RFID antenna includes a base antenna portion configured by integrating a conductive thread into the tag base, including by weaving or sewing. The RFID inlay or module may include: the IC chip; an inlay antenna portion connected to the IC chip; and a protecting member configured to protect the inlay antenna portion and the IC chip.
Other approaches also use conductive thread antennas of different shapes with epoxy resin. The conductive thread approaches result in tags with antennas that are more susceptible to breaking easily. Tags made with conductive thread typically require larger tag sizes due to the relatively greater thickness of the conductive thread. The larger tag sizes required with a conductive thread approach can damage clothing, laundry or other materials in which the tags are used.
Still other prior art approaches construct the antenna from milled foil of aluminum glued on the top of the substrate and do not use epoxy resin to strengthen connection of the platform of the chip and the connection points of antenna. Tags made using these approaches are more susceptible to damage at the connection portions between the antennas and integrated circuit.
There are prior art approaches that use silver conductive ink to print the antenna onto the surface of the substrate using a stencil printing process to provide the conductive ink on the substrate. With this approach, shapes are milled from the substrate using a stencil knife tool. But multiple layers of conductive ink cannot be applied on the same surface. This affects the reading distance and accuracy of the resulting tags.
Another approach using conductive ink for the antenna prints the ink from a jet ink printer as is described in U.S. Pat. No. 8,922,435. These approaches do not enable multiple layers of ink to be printed on the same surface which adversely affects the quality of the tag and its ability to be read in terms of accuracy and distance. Yet another approach is described in U.S. Pat. Pub. No. 2007/007344 (Inoue et al.), in which the antenna is formed using conductive paste, which has a high resistance and also results in inferior performance.
What is needed is a design for an RFID tag that is thin, flexible, durable, capable of being used and reused in a wide variety of applications, including applications where the tags are subject to water, extreme hot and cold temperatures, and other stresses which can damage or break the tags, able to be read efficiently, quickly, and in bulk using a wide variety of readers, yet be able to be produced efficiently and at a lower cost than prior art designs and methods of manufacture. The present invention achieves these advantages without the drawbacks and problems of prior art designs and provides improved performance in reading accuracy, distance, and speed.